Among steps for manufacturing a semiconductor device, in a step of grinding a semiconductor wafer, an adhesive film is attached to the semiconductor wafer in order to prevent damage of the semiconductor wafer.
As the above-described adhesive film, generally, a film obtained by laminating an ultraviolet-curable adhesive resin layer on a base material film is used. When this adhesive film is irradiated with ultraviolet rays, the adhesive resin layer cross-links, and the adhesive force of the adhesive resin layer decreases, and thus the adhesive film can be easily peeled off from the semiconductor wafer.
Meanwhile, in steps for manufacturing a semiconductor device using the above-described adhesive film, there have been cases in which static electricity called peeling charging is generated during the peeling of the adhesive film from the semiconductor wafer. There have been cases in which a circuit formed on the semiconductor wafer is broken due to the static electricity generated as described above (electrostatic breakdown) or a foreign substance such as dust is attached to a circuit formed on the semiconductor wafer.
Particularly, in response to an increase in the density of semiconductor wafers and a decrease in wire pitches in recent years, there has been a tendency that semiconductor wafers are likely to be affected by static electricity more than ever.
In consideration of the above-described circumstance, recently, for adhesive films used to prevent damage of semiconductor wafers in steps for manufacturing a semiconductor device, there has been a demand for the additional improvement in antistatic performance.
As a technique regarding an adhesive film for processing a semiconductor wafer as described above, for example, the technique described in Patent Document 1 (Japanese Unexamined Patent Publication No. 2011-210944) is exemplified.
Patent Document 1 describes an adhesive tape for processing an antistatic semiconductor which is an adhesive tape constituted of a base material film and a photocurable adhesive layer and includes an antistatic layer containing a conductive polymer in at least one surface of the base material film and an adhesive layer containing a photocurable unsaturated carbon bond in a molecule of a base polymer on the antistatic layer, in which a surface resistivity on the adhesive layer side before and after ultraviolet curing is 1×106 to 5×1012Ω/□, a thickness of the adhesive layer is 20 to 250 μm, and a 90-degree peel adhesive force (based on JIS Z 0237: a peel rate is 50 mm/min) after the ultraviolet curing of the adhesive layer in a case in which the adhesive tape is attached to a silicon mirror wafer is 0.15 to 0.25 N/25 mm.